The present invention relates to an electronic-type computer, such as a programmable desk top calculator or personal computer, into which a program is entered and then is executed.
In a conventional electronic-type computer, a program is written and entered into a Random Access Memory (RAM), then executed. Or else, a program is not written, but an all-purpose, expandable, multiple program Read Only Memory (ROM) is supplied in modular form, and those programs are selectively transferred to the RAM, and then executed.
In this conventional electronic-type computer, when using a high-level program language of the conversational form, such as Basic, the RAM which stores the programs, and the ROM, which provides control, must be of fairly large capacity memory, and such a large capacity RAM, and large capacity controlling ROM must be incorporated into the computer. The memory capacity of a RAM of large scale integrated (LSI) construction, is from one part in several tenths to one part in several hundredths of that of a packaged ROM of identical shape. Therefore, in a conventional small, portable electronic-type computer conforming to the limitations of the memory capacity of the RAM, the capacity of the program which can be run is of necessity limited, and therefore an expandable ROM program could not be effectively utilized.